Antioxidant treatment with edaravone or taurine ameliorates diabetes-induced testicular dysfunction in the rat

The Effect of Edaravone Supplementation Prior to Cryopreservation on Sperm Parameters, DNA Integrity, Apoptosis, Lipid Peroxidation, and Mitochondrial Membrane Potential in Infertile Men with Asthenoteratozoospermia

Male infertility is a worldwide problem, and many couples have suffered from it. Although cryopreservation is widely used for the long-term preservation of human sperm, sperm survival, and function post-thawing procedure may be strongly impaired and thus decrease the reproductive performance. This study examined whether adding Edaravone before cryopreservation could improve the post-thaw parameters (especially sperm motility) of cryopreserved spermatozoa in patients with asthenoteratozoospermia (AT). Semen samples were collected by masturbation from 25 men with AT and assessed following WHO standards. Samples were divided into three aliquots. The first aliquot remained untreated and freshly assessed (fresh group). The second aliquot was untreated, mixed with a cryopreservation medium, and cryopreserved (freeze group). The third aliquot was treated with ten µM Edaravone, mixed with cryopreservation medium, and cryopreserved (freeze + Edaravone group). The groups were assessed for motility, morphology, viability, apoptosis, lipid peroxidation, Mitochondrial Membrane Potential (MMP), DNA Fragmentation Index (DFI), glutathione (GSH), ATP, and ROS production. The freeze + Edaravone group significantly improved total sperm motility (P < 0.0001), progressive and non-progressive sperm motility (P < 0.01), viability (P < 0.0001), morphology (P < 0.001), DFI (P < 0.0001) and live sperm cells (P < 0.0001) post-thawing compared to freeze group. Additionally, the freeze + Edaravone group significantly decreased necrotic sperm cells (P < 0.0001), lipid peroxidation (P < 0.0001), and intracellular ROS production (P < 0.0001) post-thawing procedure. Furthermore, the freeze + Edaravone group significantly enhanced MMP jc-1 orange and green (P < 0.0001 and P < 0.01, respectively), ATP production (P < 0.0001), and GSH levels (P < 0.0001) post-thawing procedure compared to freeze group. Our findings proved that the freeze + Edaravone group of men with AT improved sperm survival and functions post-thawing procedure.

Modulatory role of Coriandrum sativum (coriander) extract against diabetic complications on the gonads of female rats and their offspring

It is well known that diabetes is associated with impairment of ovarian and testicular structure and function. Coriander (Coriandrum sativum L.) is identified as one of the oldest herbal plants valued for its nutritional and medicinal properties. This work is mainly designed to evaluate the possible modulatory role of dry coriander fruit extract against gonadal impairments associated with diabetes in female rats and their pups. Twenty-four pregnant rats were divided into four groups (n = 6): group I served as control, group II was administered daily with coriander fruit extract (250 mg/kg b.wt), group III was injected interaperitoneally with a single dose of streptozotocin (STZ) (80 mg/kg b.wt), and group IV was injected with single dose of STZ and post administered coriander extract. The experiment was conducted from the 4th day of gestation till the end of weaning. At the end of the experiment, the mothers' rats and their offspring were weighed, sacrificed, the ovaries from mothers as well as ovaries and testes from offspring were immediately excised, and processed for histological, immunohistochemical and evaluation of apoptosis and transforming growth factorβ (TGF-β). Also, blood samples were collected and analyzed to estimate the levels of sex hormones as well as antioxidants.In STZ induced diabetes in mother's rats and their offspring, the ovarian sections revealed severe histopathological signs included several atretic follicles, dilated and congested blood capillaries. Additionally, the testicular sections of offspring appeared with destructive seminiferous tubules. Immunohistochemically, the ovarian sections displayed weak to negative expression for calretinin marker however the testicular sections showed strong expression for Bax protein (apoptotic marker) and weak to negative expression for Ki67 protein (proliferative marker). Also, the mean % values of positively expressed cells for TGF-β and annexin-v markers (late and early apoptosis indicator) were significantly elevated in the ovarian and testicular tissues of STZ-induced group of mother's rats and their pups if compared with control. Further results revealed that the levels of insulin, FSH, LH, estrogen, SOD and CAT were significantly decreased if compared with control however the levels of MDA and NO were significantly elevated. Administration of coriander fruit extract to diabetic rats successfully alleviated most of the altered histological, immunohistochemical, biochemical, and apoptotic changes induced by diabetes. Coriandrum sativum fruit extract has a powerful ameliorative role against STZ-induced diabetic gonadal dysfunctions in female rats and their offspring.

The Effects of N-acetylcysteine on Transient Receptor Potential Melastatin 2 Channels Activation and Expression in Testicular Tissue of Diabetic Rats

INTRODUCTION

Diabetes mellitus (DM) is a common, chronic metabolic disease that has harmful effects on many diverse tissues, including the testis. One of the ways of tissue damage is the modification of transient receptor potential melastatin 2 (TRPM2) channels by increased reactive oxygen species (ROS). In our study for the first time, it was aimed to investigate TRPM2 channel activation in testicular tissues of diabetic rats induced by streptozotosin (STZ) and to examine the efficacy of N-acetylcysteine (NAC) treatment, which is an antioxidant.

METHODS

In our study, 28 Wistar albino male rats aged 8-10 weeks were used, and animals were divided into four groups: control group, NAC group, DM group, and DM + NAC group. The experimental phase was designed as eight weeks. The malondialdehyde (MDA) level, which is an indicator for lipid peroxidation due to oxidative stress, was measured by the spectrophotometric method. The Tunel assay was used to determine apoptosis on testicular tissue. TRPM2 immunoreactivity was determined by the avidin-biotin-peroxidase complex method, and quantitative polymerase chain reaction (QPCR) was used to determine TRPM2 expression levels.

RESULTS

It was seen that MDA levels were significantly increased in the DM group and decreased after NAC treatment. Similarly, it was observed that apoptosis levels, which increased significantly in diabetic rats, decreased to the levels of the control group after treatment. It was seen that TRPM2 activation and expression levels were significantly decreased in the DM group.

CONCLUSION

 The results of this study show that NAC regulates TRPM2 activation in the testicular tissue of patients with diabetes and has tissue-protective properties.

Edaravone alleviates methotrexate-induced testicular injury in rats: Implications on inflammation, steroidogenesis, and Akt/p53 signaling

Edaravone (ED) is a neuroprotective drug with beneficial effects against several disorders due to its prominent antioxidant activity. However, its effect against methotrexate (MTX)-induced testicular damage was not previously investigated. Therefore, we aimed to investigate the ability of ED to prevent the oxidative stress, inflammation, and apoptosis induced by MTX on the rat testis and to examine whether ED administration modulated the Akt/p53 signaling and steroidogenesis process. Rats were allocated into; Normal, ED (20 mg/kg, PO, for 10 days), MTX (20 mg/kg, i.p., on the 5^th day), and ED + MTX groups. The results showed that MTX group exhibited higher serum activities of ALT, AST, ALP, and LDH in addition to histopathological alterations in the rat testis, compared to normal group. Furthermore, MTX induced down-regulation of the steroidogenic genes; StAR, CYP11a1, and HSD17B3 and reduced FSH, LH, and testosterone levels. The MTX group also showed higher levels of MDA, NO, MPO, NF-kB, TNF-α, IL-6, IL-1β, Bax, and caspase 3, as well as, lower levels of GSH, GPx, SOD, IL-10, Bcl2 compared to normal rats, p < 0.05. In addition, MTX treatment resulted in increased p53 expression and decreased p-Akt expression. Remarkably, ED administration significantly prevented all the biochemical, genetic, and histological damage induced by MTX. Hence, ED treatment protected the rat testis from apoptosis, oxidative stress, inflammation, and impaired steroidogenesis induced by MTX. This novel protective effect was mediated by decreasing p53 while increasing p-Akt protein expression.

The role of taurine in male reproduction: Physiology, pathology and toxicology

Taurine, a sulfur-containing amino acid, has a wide range of biological effects, such as bile salt formation, osmotic regulation, oxidative stress inhibition, immunomodulation and neuromodulation. Taurine has been proved to be synthesized and abundant in male reproductive organs. Recently, accumulating data showed that taurine has a potential protective effect on reproductive function of male animals. In physiology, taurine can promote the endocrine function of the hypothalamus-pituitary-testis (HPT) axis, testicular tissue development, spermatogenesis and maturation, delay the aging of testicular structure and function, maintain the homeostasis of the testicular environment, and enhance sexual ability. In pathology, taurine supplement may be beneficial to alleviate pathological damage of male reproductive system, including oxidative damage of sperm preservation in vitro, testicular reperfusion injury and diabetes -induced reproductive complications. In addition, taurine acts as a protective agent against toxic damage to the male reproductive system by exogenous substances (e.g., therapeutic drugs, environmental pollutants, radiation). Related mechanisms include reduced oxidative stress, increased antioxidant capacity, inhibited inflammation and apoptosis, restored the secretory activity of the HPT axis, reduced chromosomal variation, enhanced sperm mitochondrial energy metabolism, cell membrane stabilization effect, etc. Therefore, this article reviewed the protective effect of taurine on male reproductive function and its detailed mechanism, in order to provide reference for further research and clinical application.

Arthrospira platensis nanoparticles defeat against diabetes-induced testicular injury in rat targeting, oxidative, apoptotic, and steroidogenesis pathways

Varieties of studies have been used to investigate the health benefits of Spirulina (Arthrospira platensis); however, more research is needed to examine if its nano form may be utilized to treat or prevent several chronic diseases. So, we designed this study to explore the effect and the cellular intracellular mechanisms by which Arthrospira platensis Nanoparticles (NSP) alleviates the testicular injury induced by diabetes in male Wistar rats. Eighty Wistar male rats (n = 80) were randomly allocated into eight groups. Group 1 is untreated rats (control), Group 2 including STZ-induced diabetic rats with 65 mg/kg body weight STZ (STZ-diabetic), Group 3-5: including diabetic rats treated with NSP1, NSP2, and NSP3 at 0.25, 0.5, and 1 mg/kg body weight, respectively, once daily orally by the aid of gastric gavage for 12 consecutive weeks and groups 6-8 include normal rats received NSP (0.25, 0.5, and 1 mg/kg body weight once daily orally. The identical volume of normal saline was injected into both control and diabetic rats. After 12 weeks of diabetes induction, the rats were killed. According to our findings, NSP administration to diabetic rats enhances the total body weight and the weight of testes and accessory glands; in addition, NSP significantly reduced nitric oxide and malondialdehyde in testicular tissue improved sperm parameters. Intriguingly, it raises testicular GSH and SOD activity by a significant amount (p < 0.05). As well, Oral administration of NSP to diabetic rats resulted in a decrease in the blood glucose levels, HA1C, induced in the diabetic group, which overcame the diabetic complications NSP caused down-regulation of apoptotic genes with upregulation of BCL-2 mRNA expression (p < 0.05) and prominent up-regulation of steroidogenesis genes expression level in testes in comparison to the diabetic rats which resulted in improving the decreased levels of testosterone hormone, FSH, and LH induced by diabetes. In the same way, our histopathological findings support our biochemical and molecular findings; in conclusion, NSP exerted a protective effect against reproductive dysfunction induced by diabetes not only through its high antioxidant and hypoglycemic action but also through its down-regulation of Apoptotic genes and up-regulation of steroidogenesis regulatory genes expression level in diabetic testes.

Involvement of TauT/SLC6A6 in Taurine Transport at the Blood-Testis Barrier

Taurine transport was investigated at the blood–testis barrier (BTB) formed by Sertoli cells. An integration plot analysis of mice showed the apparent influx permeability clearance of [³H]taurine (27.7 μL/(min·g testis)), which was much higher than that of a non-permeable paracellular marker, suggesting blood-to-testis transport of taurine, which may involve a facilitative taurine transport system at the BTB. A mouse Sertoli cell line, TM4 cells, showed temperature- and concentration-dependent [³H]taurine uptake with a K_m of 13.5 μM, suggesting that the influx transport of taurine at the BTB involves a carrier-mediated process. [³H]Taurine uptake by TM4 cells was significantly reduced by the substrates of taurine transporter (TauT/SLC6A6), such as β-alanine, hypotaurine, γ-aminobutyric acid (GABA), and guanidinoacetic acid (GAA), with no significant effect shown by L-alanine, probenecid, and L-leucine. In addition, the concentration-dependent inhibition of [³H]taurine uptake revealed an IC₅₀ of 378 μM for GABA. Protein expression of TauT in the testis, seminiferous tubules, and TM4 cells was confirmed by Western blot analysis and immunohistochemistry by means of anti-TauT antibodies, and knockdown of TauT showed significantly decreased [³H]taurine uptake by TM4 cells. These results suggest the involvement of TauT in the transport of taurine at the BTB.

Taurine as a Natural Antioxidant: From Direct Antioxidant Effects to Protective Action in Various Toxicological Models

Natural antioxidants have received tremendous attention over the last 3 decades. At the same time, the attitude to free radicals is slowly changing, and their signalling role in adaptation to stress has recently received a lot of attention. Among many different antioxidants in the body, taurine (Tau), a sulphur-containing non-proteinogenic β-amino acid, is shown to have a special place as an important natural modulator of the antioxidant defence networks. Indeed, Tau is synthesised in most mammals and birds, and the Tau requirement is met by both synthesis and food/feed supply. From the analysis of recent data, it could be concluded that the direct antioxidant effect of Tau due to scavenging free radicals is limited and could be expected only in a few mammalian/avian tissues (e.g., heart and eye) with comparatively high (>15-20 mM) Tau concentrations. The stabilising effects of Tau on mitochondria, a prime site of free radical formation, are characterised and deserve more attention. Tau deficiency has been shown to compromise the electron transport chain in mitochondria and significantly increase free radical production. It seems likely that by maintaining the optimal Tau status of mitochondria, it is possible to control free radical production. Tau's antioxidant protective action is of great importance in various stress conditions in human life, and is related to commercial animal and poultry production. In various in vitro and in vivo toxicological models, Tau showed AO protective effects. The membrane-stabilizing effects, inhibiting effects on ROS-producing enzymes, as well as the indirect AO effects of Tau via redox balance maintenance associated with the modulation of various transcription factors (e.g., Nrf2 and NF-κB) and vitagenes could also contribute to its protective action in stress conditions, and thus deserve more attention.

Redox Balance in Male Infertility: Excellence through Moderation-"Μέτρον ἄριστον"

Male infertility, a relatively common and multifactorial medical condition, affects approximately 15% of couples globally. Based on WHO estimates, a staggering 190 million people struggle with this health condition, and male factor is the sole or contributing factor in roughly 20–50% of these cases. Nowadays, urologists are confronted with a wide spectrum of conditions ranging from the typical infertile male to more complex cases of either unexplained or idiopathic male infertility, requiring a specific patient-tailored diagnostic approach and management. Strikingly enough, no identifiable cause in routine workup can be found in 30% to 50% of infertile males. The medical term male oxidative stress infertility (MOSI) was recently coined to describe infertile men with abnormal sperm parameters and oxidative stress (OS), including those previously classified as having idiopathic infertility. OS is a critical component of male infertility, entailing an imbalance between reactive oxygen species (ROS) and antioxidants. ROS abundance has been implicated in sperm abnormalities, while the exact impact on fertilization and pregnancy has long been a subject of considerable debate. In an attempt to counteract the deleterious effects of OS, urologists resorted to antioxidant supplementation. Mounting evidence indicates that indiscriminate consumption of antioxidants has led in some cases to sperm cell damage through a reductive-stress-induced state. The “antioxidant paradox”, one of the biggest andrological challenges, remains a lurking danger that needs to be carefully avoided and thoroughly investigated. For that reason, oxidation-reduction potential (ORP) emerged as a viable ancillary tool to basic semen analysis, measuring the overall balance between oxidants and antioxidants (reductants). A novel biomarker, the Male infertility Oxidative System (MiOXSYS^®), is a paradigm shift towards that goal, offering a quantification of OS via a quick, reliable, and reproducible measurement of the ORP. Moderation or “Μέτρον” according to the ancient Greeks is the key to successfully safeguarding redox balance, with MiOXSYS^® earnestly claiming its position as a guarantor of homeostasis in the intracellular redox milieu. In the present paper, we aim to offer a narrative summary of evidence relevant to redox regulation in male reproduction, analyze the impact of OS and reductive stress on sperm function, and shed light on the “antioxidant paradox” phenomenon. Finally, we examine the most up-to-date scientific literature regarding ORP and its measurement by the recently developed MiOXSYS^® assay.

Redox treatment ameliorates diabetes mellitus-induced skin flap necrosis via inhibiting apoptosis and promoting neoangiogenesis

Intractable wound healing is the habitual problem of diabetes mellitus. High blood glucose limits wound healing by interrupting inflammatory responses and inhibiting neoangiogenesis. Oxidative stress is commonly thought to be a major pathogenic cause of diabetic complications. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one, EDV) is a free radical scavenger which suppress oxidative stress. This study investigates whether EDV can reduce oxidative stress in wound healing HaCaT/human dermal fibroblasts cells (HDFs) in vitro and in vivo animal model. Cell viability and wound healing assays, FACS flow cytometry, and Hoechst 33342 staining were performed to confirm apoptosis and cytotoxicity in H2O2 and EDV-treated HaCaT and HDFs. A streptozotocin-induced hyperglycemic animal model was made in adult C57BL6 mice. Full-thickness skin flap was made on dorsomedial back and re-sutured to evaluate the wound healing process. EDV was delivered slowly in the skin flap with degradable fibrin glue. The flap was monitored and analyzed on postoperative days 1, 3, and 5. CD31/DAPI staining was done to detect newly formed blood vessels. The expression levels of NF-κB, bcl-2, NOX3, and STAT3 proteins in C57BL6 mouse tissues were also examined. The wound healing process in hyper- and normoglycemic mice showed a difference in protein expression, especially in oxidative stress management and angiogenesis. Exogenous H2O2 reduced cell viability in a proportion to the concentration via apoptosis. EDV protected HaCaT cells and HDFs from H2O2 induced reactive oxygen species cell damage and apoptosis. In the mouse model, EDV with fibrin resulted in less necrotic areas and increased angiogenesis on postoperative day 5, compared to sham-treated mice. Our results indicate that EDV could protect H2O2-induced cellular injury via inhibiting early apoptosis and inflammation and also increasing angiogenesis. EDV might be valuable in the treatment of diabetic wounds that oxidative stress has been implicated.

SMTP-44D improves diabetic neuropathy symptoms in mice through its antioxidant and anti-inflammatory activities

Diabetic neuropathy (DN) is one of the major complications of diabetes. However, there are few approved effective therapies for painful or insensate DN. Recent studies have implicated oxidative stress and inflammation in the pathogenesis of DN, and suppressing these could be an important therapeutic strategy. We previously reported that Stachybotrys microspora triprenyl phenol-44D (SMTP-44D) exhibits both antioxidant and anti-inflammatory activities. The aim of this study was to evaluate the effects of SMTP-44D in a mouse model of streptozotocin-induced DN. SMTP-44D was administered for 3 weeks after the disease induction, and its effects were evaluated on the basis of mechanical and thermal thresholds, blood flow in the bilateral hind paw, and blood flow and conduction velocity in the sciatic nerve. Furthermore, the levels of inflammatory factors, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6 and malondialdehyde (MDA), in the sciatic nerve were assessed. Neurological degeneration was assessed by measuring myelin thickness and g-ratio in the sciatic nerve. SMTP-44D treatment significantly improved allodynia, hyperalgesia, blood flow, and conduction velocity in DN model mice in a dose-dependent manner. Neurological degeneration was also significantly improved, accompanied by decreased levels of inflammatory factors (TNF-α, 57.8%; IL-1β, 51.4%; IL-6, 62.8%; and MDA, 40.7% reduction rate against the diabetes mellitus + normal saline group). Thus, SMTP-44D can improve allodynia and hyperalgesia in DN without affecting the body weight and blood glucose levels, which may be due to its antioxidant and anti-inflammatory properties. In conclusion, SMTP-44D could be a potential therapeutic agent for the treatment of DN.

Clusterin suppresses spermatogenic cell apoptosis to alleviate diabetes-induced testicular damage by inhibiting autophagy via the PI3K/AKT/mTOR axis

BACKGROUND INFORMATION

Diabetes-induced testicular dysfunction is characterised by abnormal apoptosis of spermatogenic cells, but the underlying mechanism is poorly understood. This study aimed to investigate the roles of clusterin (CLU) in testicular damage associated with diabetes pathogenesis, as well as the molecular mechanism. A rat diabetes model was established using streptozocin, and the mouse spermatogenic cell line GC-1 spg was treated with high glucose as a cellular model. CLU was overexpressed in GC-1 spg cells, followed by detection of serum testosterone, cell proliferation, cell apoptosis and autophagy.

RESULTS

CLU expression was significantly reduced and LC3 expression was elevated in testis tissues in the rat diabetes model and high glucose-treated GC-1 spg cells. High glucose led to suppressed viability, enhanced apoptosis, reduced Bcl-2 expression, elevated Bax expression and cleavage of Caspase-3/-9 in GC-1 spg cells, and these effects were abrogated by CLU overexpression. Additionally, CLU overexpression repressed LC3 and Beclin-1 expression, reduced the LC3II/LC3I ratio and promoted p62 expression in GC-1 spg cells in the presence of high glucose, and these effects were all mitigated by rapamycin treatment. Inhibition of PI3K/AKT/mTOR signalling with LY294002 activated autophagy in CLU-overexpressing GC-1 spg cells under high glucose conditions. CLU overexpression repressed autophagy and alleviated testicular damage in diabetic rats, which was also abrogated by LY294002 treatment.

CONCLUSIONS

CLU expression is suppressed during diabetes-induced testicular damage, whereas CLU overexpression alleviates diabetes-induced testicular damage by activating PI3K/AKT/mTOR signalling to inhibit autophagy and further repress spermatogenic cell apoptosis.

Oxidative Stress Alterations in the Bladder of a Short-period Type 2 Diabetes Rat Model: Antioxidant Treatment Can Be Beneficial for the Bladder

BACKGROUND/AIM

A short-period type 2 diabetes model was established in order to identify changes in oxidative stress in the bladder at the initiation of the disease. The effect of antioxidant treatment was examined.

MATERIALS AND METHODS

Diabetes was induced in adult male Wistar rats with a single dose of streptozotocin (40 mg/kg; i.p.). Diabetic animals were then randomly separated into three groups: No treatment (DM), resveratrol treatment, and taurine treatment, and fed with a high-fat diet. Age-matched non-diabetic animals were used and fed with normal diet (control). Two weeks later, animals were sacrificed and bladders were processed for histological evaluation, and further analysis for oxidative stress markers.

RESULTS

The body weight of all diabetic animals was significantly lower compared to the controls. The DM group demonstrated a significantly higher bladder weight to body weight ratio compared to the control. The bladder in the DM group demonstrated abruption of the mucosa from the muscularis and edema in the transitional epithelium. Bladders from the resveratrol-, and taurine-treated groups did not demonstrate these histological alterations. The level of malondialdehyde (MDA) in the bladder was significantly higher in the DM group compared to all other groups. Immunohistochemistry showed that diabetes induced a moderate to strong expression of oxidative stress markers MDA and 4-hydroxynonenal, and DNA oxidative stress marker 8-deoxyguanosine in the DM group compared to the other groups.

CONCLUSION

Prompt diagnosis and treatment of diabetes is crucial in regard to disease progression. Specifically, in the bladder it appears that both mild damage at the structural level, as well as oxidative damage at the molecular level may be prevented by antioxidant treatment.

Benefits of the consumption of Brazil nut (Bertholletia excelsa) extract in male reproductive parameters of streptozotocin-induced diabetic rats

Objective

The objective of this study was to evaluate the effects of intake of Brazil nut extract (BN) or sodium selenite solution on reproductive parameters of male diabetic animals.

Methods

A total of 48 Wistar rats were distributed into six groups: diabetes (n = 8); diabetes and Brazil nut extract (n = 8); diabetes and sodium selenite (Na₂SeO₃) (n = 8); Brazil nut extract (n = 8); sodium selenite (n = 8) and control (n = 8). A single dose of streptozotocin (65 mg/kg) was injected intravenously to the rats to induce diabetes. BN or Na₂SeO₃ were administered by gavage for 56 days.

Results

The diabetes caused critical alterations on body mass gain, reproductive parameters and antioxidant capacity. Treatments with both BN or Na₂SeO₃ were able to increase significantly the glutathione peroxidase and the daily sperm production, both in diabetic (p < 0.01 and p < 0.05) and in healthy animals (p < 0.01 and p < 0.05).

Conclusion

The Brazil nut extract and sodium selenite were able to improve some reproductive parameters of diabetic rats. Moreover, we could infer that this effect is probably due to the natural selenium content of the BN.

Taurine ameliorates oxidative stress induced inflammation and ER stress mediated testicular damage in STZ-induced diabetic Wistar rats

One of the major consequences of diabetes is reproductive dysfunction but the fundamental mechanisms are still poorly known. The objective of the present study was to explore the beneficial role of taurine against streptozotocin induced testicular dysfunctions in diabetic male Wister rats and understanding the underlying intricate molecular mechanisms. Exposure to streptozotocin (50 mg kg-1 body weight, i.p., once) elevated blood glucose level, induced testicular histological alterations and reduced testis-to-body weight ratio, serum testosterone, testicular markers and activity of antioxidant enzymes. Generation of ER stress (increased expression of calpain-1, caspase-12 and upregulation of CHOP, GRP78 via eIF2α signaling), translocation of NF κB in the nucleus (leading to the upregulation in the levels of inflammatory cytokines), activation of mitochondria dependent apoptotic pathway and DNA fragmentation were revealed from this study. However, administration of taurine at a dose of 100 mg kg-1 body weight for 6 weeks post diabetic induction, successfully ameliorated all these adverse effects. Thus, taurine, as a potential therapeutic agent, may hold promise in preventing oxidative and ER stress mediated diabetic testicular complications in rats.

Taurine Improves Sexual Function in Streptozotocin-Induced Diabetic Rats

Previous studies have identified that diabetic erectile dysfunction is associated with androgen and nitric oxide deficiency resulting from hyperglycemia. It has been demonstrated that taurine can stimulate testosterone secretion, increase nitric oxide synthase (NOS) activity and nitric oxide (NO) production, and reduce blood glucose levels in the diabetic animals. Furthermore, recent studies have found that taurine relaxes both the corpus cavernosum and the vasculature. Accordingly, we hypothesized that taurine might exert beneficial effects on erectile function of the diabetic rats. Here, we assessed the effects of taurine on sexual function in streptozotocin (STZ) -induced diabetic male rats. We observed that taurine treatment could markedly increase sexual response and mating ability of STZ-diabetic rats. The serum concentration of gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH), follicle-stimulating hormone (FSH) and testosterone (T) were also significantly increased by taurine administration. Importantly, taurine supplementation notably increased mRNA levels and activity of endothelial NOS (eNOS) and neuronal NOS (nNOS), as well as NO and cGMP content, in the corpus cavernosum of the diabetic rats. In conclusion, the present data indicate that taurine can increase sexual function of STZ-induced diabetic male rats mainly by correcting the diabetes, increasing sexual desire, which is implicated in ameliorating the hypothalamic-pituitary-testicular axis function, and by improving penile erection, which requires increased signaling from the penile endothelial- and neuronal-dependent NO-cGMP pathway.

Curcumin Attenuates Testicular Injury in Rats with Streptozotocin-Induced Diabetes

Oxidative damage, inflammation, and apoptosis are the primary features of diabetic testicular damage. Curcumin protects against diabetic testicular injury, but the underlying mechanisms remain obscure. This study examined the effect of curcumin on type 2 diabetes mellitus- (T2DM-) induced testicular injury, oxidative stress, and apoptotic changes. T2DM rats were intraperitoneally injected with 40 mg/kg STZ after being fed a high-fat diet for 8 weeks. One week after STZ injection, 100 or 200 mg/kg curcumin was administered orally to the diabetic rats for 16 weeks. Histological changes in the testes were determined by HE staining. Serum testosterone was measured. Markers of superoxide levels, such as SOD activity and MDA content, and markers of cell death, including the expression of Bax, Bcl-2, and MAPK family members, were measured by molecular biology or immunohistochemical techniques. Degeneration and disruption of seminiferous tubule structure were observed in diabetic rats. Serum testosterone levels were markedly lower in diabetic rats than in control rats. Moreover, testicular apoptosis and Bax expression were much higher in diabetic rats than in control rats. Superoxide generation, the NADP⁺/NADPH ratio, and NADPH oxidase subunit expression, including expression of the gp91^phox, p47^phox, and p67^phox subunits, increased, while antioxidant enzyme levels decreased in diabetic rats. Furthermore, the MAPK signaling pathway was activated in diabetic rats. Curcumin partially prevented diabetes-induced microstructural abnormalities and significantly increased serum testosterone levels compared to untreated T2DM rats. Additionally, curcumin reduced testicular apoptosis by regulating apoptotic proteins and markedly inhibited oxidative stress levels by downregulating MDA expression, decreasing NADPH activity, and restoring antioxidant enzymes. Remarkably, curcumin treatment also suppressed MAPK activation. Thus, curcumin may have therapeutic value in the treatment of diabetes-induced testicular injury due to its prevention of testicular apoptosis and attenuation of oxidative stress.

Impact of antioxidants on seminal vesicles function and fertilizing potential in diabetic rats

Diabetes mellitus significantly affects the male reproduction and sexual function. In the present study, we investigated the diabetes-induced dysfunction of seminal vesicles (SVs) in the diabetes-rat model and the role of antioxidants. Streptozotocin-induced diabetes after 4 weeks caused smaller size of the organs, hypercontractility, histological abnormalities, increased concentrations of malondialdehyde in the serum and tissue, overexpression of oxidative stress markers, and cleaved caspase-3 as identified by immunohistochemistry in the SVs. In addition, diabetes resulted in deceased levels of serum testosterone and no newborns after the mating studies. Antioxidants significantly normalized all the above parameters, except for the severely decreased serum testosterone levels and the negative outcome of the mating studies. The present study gives evidence for the important role of diabetes-induced oxidative stress in the function and structure of these androgen-dependent organs. Antioxidants may be a promising supplementary therapy for diabetic male patients to alleviate ejaculatory disorders but alone is not efficient treatment for the mitigation of infertility.

Prophylactic role of taurine and its derivatives against diabetes mellitus and its related complications

Taurine is a conditionally essential amino acid present in the body in free form. Mammalian taurine is synthesized in the pancreas via the cysteine sulfinic acid pathway. Anti-oxidation and anti-inflammation are two main properties through which it exerts its therapeutic effects. Many studies have shown its excellent therapeutic potential against diabetes mellitus and related complications like diabetic neuropathy, retinopathy, nephropathy, hematological dysfunctions, reproductive dysfunctions, liver and pancreas related complications etc. Not only taurine, a number of its derivatives have also been reported to be important in ameliorating diabetic complications. The present review has been aimed to describe the importance of taurine and its derivatives against diabetic metabolic syndrome and related complications.

Quail (Coturnix japonica) egg yolk bioactive components attenuate streptozotocin-induced testicular damage and oxidative stress in diabetic rats

INTRODUCTION

The testicular milieu is the machinery for the metabolism of testosterone in the male reproductive system.

PURPOSE

The dysfunction of this highly regenerating system is inevitable in the condition of glucose imbalance as a result of insulin machinery impairment. Therefore, it is imperative to recommend dietary intervention for attenuating the testicular dysfunction and oxidative stress resulting from STZ-induction of diabetes.

METHODS

STZ-induced diabetes (65 mg/kg, ip) was treated with QEYEM (50, 100 and 200 mg/kg/day) and quercetin (50 mg/kg/day) for 7weeks. In serum, glucose, testosterone, IL-6 and TNF-α levels were estimated, and in testis, tissues TBARS, sulfhydryl groups, nucleic acids and total protein (TP) levels were estimated. SOD, CAT and GST activities were also determined in testicular cells. Histopathological changes were evaluated in a cross-section of testis.

RESULTS

Testosterone concentration was decreased while pro-inflammatory markers were increased in STZ-assaulted rats. Treatment using QEYEM of diabetic rats corrected assaults and reverse significantly the diabetic conditions. QEYEM-treated groups showed significant inhibition of TBARS levels and elevation of testicular GSH, NP-SH, total protein (TP) and nucleic acids-DNA and RNA levels. The QEYEM administration reversed the inhibited activities of SOD, CAT and GST in testicular cells in diabetic rats. The characterization of the extract carried out through HPLC analytical techniques revealed vitamins A, D and E concentrations of 0.645, 0.012 and 6.3 mg/100 g, respectively.

CONCLUSION

QEYEM supplementation to STZ-induced diabetic rats for seven (7) consecutive weeks is a potential intervention against testicular damage in adult diabetic rats, probably by decreasing oxidative stress.

Antioxidant treatment ameliorates diabetes-induced dysfunction of the vas deferens in a rat model

Diabetes mellitus (DM) affects the male ejaculatory function. This study was designed to evaluate the role of oxidative stress in the development of diabetes-induced dysfunction of vas deferens (VD) in the rat. DM was induced by streptozotocin in 40 male Wistar rats. Subsequently, the diabetic animals were divided into three groups: DM group, DM + Eda group and DM + Tau group. These groups were administered saline, edaravone and taurine, respectively, daily for 4 weeks. Another group of ten rats served as a control group. DM was diagnosed in the 40 streptozotocin-injected rats. DM significantly reduced the VD weight. Additionally, DM induced in vitro VD hypercontractility, VD histological abnormalities and increased the serum and VD tissue concentration of malondialdehyde. VD immunohistochemistry revealed overexpression of three markers of oxidative stress. DM significantly reduced serum testosterone levels. No live birth was documented in all DM rats in mating experiments. Antioxidants significantly improved all the aforementioned parameters, except the testosterone levels. This study indicates a deleterious impact of DM-induced oxidative stress on VD histological and functional features. Antioxidant treatment may provide an adjunct tool to alleviate ejaculatory disorders for male patients with type 1 diabetes.

The calcium-sensing receptor participates in testicular damage in streptozotocin-induced diabetic rats

Male infertility caused by testicular damage is one of the complications of diabetes mellitus. The calcium-sensing receptor (CaSR) is expressed in testicular tissues and plays a pivotal role in calcium homeostasis by activating cellular signaling pathways, but its role in testicular damage induced by diabetes remains unclear. A diabetic model was established by a single intraperitoneal injection of streptozotocin (STZ, 40 mg kg-1 ) in Wistar rats. Animals then received GdCl 3 (an agonist of CaSR, 8.67 mg kg-1 ), NPS-2390 (an antagonist of CaSR, 0.20 g kg-1 ), or a combination of both 2 months after STZ injection. Diabetic rats had significantly lower testes weights and serum levels of testosterone compared to healthy rats, indicating testicular damage and dysfunction in STZ-induced diabetic rats. Compared with healthy controls, the testicular tissues of diabetic rats overexpressed the CaSR protein and had higher levels of malondialdehyde (MDA), lower superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, and higher numbers of apoptotic germ cells. The testicular tissues from diabetic rats also expressed lower levels of Bcl-2 and higher levels of Bax and cleaved caspase-3 in addition to higher phosphorylation rates of c-Jun NH 2 -terminal protein kinase (JNK), p38, and extracellular signaling-regulated kinase (ERK) 1/2. The above parameters could be further increased or aggravated by the administration of GdCl 3 , but could be attenuated by injection of NPS-2390. In conclusion, the present results indicate that CaSR activation participates in diabetes-induced testicular damage, implying CaSR may be a potential target for protective strategies against diabetes-induced testicular damage and could help to prevent infertility in diabetic men.

Amelioration of nandrolone decanoate-induced testicular and sperm toxicity in rats by taurine: effects on steroidogenesis, redox and inflammatory cascades, and intrinsic apoptotic pathway

The wide abuse of the anabolic steroid nandrolone decanoate by athletes and adolescents for enhancement of sporting performance and physical appearance may be associated with testicular toxicity and infertility. On the other hand, taurine; a free β-amino acid with remarkable antioxidant activity, is used in taurine-enriched beverages to boost the muscular power of athletes. Therefore, the purpose of this study was to investigate the mechanisms of the possible protective effects of taurine on nandrolone decanoate-induced testicular and sperm toxicity in rats. To achieve this aim, male Wistar rats were randomly distributed into four groups and administered either vehicle, nandrolone decanoate (10mg/kg/week, I.M.), taurine (100mg/kg/day, p.o.) or combination of taurine and nandrolone decanoate, for 8 successive weeks. Results of the present study showed that taurine reversed nandrolone decanoate-induced perturbations in sperm characteristics, normalized serum testosterone level, and restored the activities of the key steroidogenic enzymes; 3β-HSD, and 17β-HSD. Moreover, taurine prevented nandrolone decanoate-induced testicular toxicity and DNA damage by virtue of its antioxidant, anti-inflammatory, and anti-apoptotic effects. This was evidenced by taurine-induced modulation of testicular LDH-x activity, redox markers (MDA, NO, GSH contents, and SOD activity), inflammatory indices (TNF-α, ICAM-1 levels, and MMP-9 gene expression), intrinsic apoptotic pathway (cytochrome c gene expression and caspase-3 content), and oxidative DNA damage markers (8-OHdG level and comet assay). In conclusion, at the biochemical and histological levels, taurine attenuated nandrolone decanoate-induced poor sperm quality and testicular toxicity in rats.

Diabetes-induced oxidative DNA damage alters p53-p21CIP1/Waf1 signaling in the rat testis

Diabetes is increasingly becoming a major cause of large-scale morbidity and mortality. Diabetes-induced oxidative stress alters numerous intracellular signaling pathways. Although testicular dysfunction is a major concern in diabetic men, the mechanistic alterations in the testes that lead to hypogonadism are not yet clear. Oxidative mitochondrial DNA damage, as indicated by 7,8-dihydro-8-oxo-2'-deoxyguanosine, and phosphorylation of p53 at ser315 residue (p-p53ser315) increased in a stage- and cell-specific manner in the testes of rats that were diabetic for 1 month (DM1). Prolongation of diabetes for 3 months (DM3) led to an increase in nuclear oxidative DNA damage in conjunction with a decrease in the expression of p-p53ser315. The nuclei of pachytene and preleptotene spermatocytes, steps 1, 11, and 12 spermatids, secondary spermatocytes and the Sertoli cells, and the meiotic figures showed an increase in the expression of p-p53ser315. An increase in the expression of a downstream target of p53 and protein 21(cyclin-dependent kinase interacting protein 1/wild-type p53-activated factor 1) (p21(CIP1/Waf1)) in both diabetic groups did not show any time-dependent effects but occurred concurrent with an upregulation of p-p53ser315 in DM1 and a downregulation of the protein in DM3. In diabetic groups, the expression of p21(CIP1/Waf1) was mainly cytoplasmic but also perinuclear in pachytene spermatocytes and round spermatids. The cytoplasmic localization of p21(CIP1/Waf1) may be suggestive of an antiapoptotic role for the protein. The perinuclear localization is probably related to the cell cycle arrest meant for DNA damage repair. Diabetes upregulates p21(CIP1/Waf1) signaling in testicular germ cells in association with alteration in p-p53ser315 expression, probably to counteract DNA damage-induced cell death.